Education

Ph.D. Stanford University M.S. University of New Hampshire, Durham B.A. University of New Hampshire, Durham

Current Research and Teaching

Cytokinesis, the process by which a cell constricts at the equator to ultimately divide into two daughter cells remains poorly understood. My primary interest has been to identify the proteins/genes involved in both the mechanics and the regulation of this process. To achieve this goal my lab uses the cellular slime mold Dictyostelium discoideum. Using Dictyostelium a molecular genetic screen was developed to identify the genes required for cytokinesis. Several genes were subsequently identified and we are in the process of describing how these genes participate in the regulation of cytokinesis. One of these genes codes for a novel small GTP-binding protein of the ras superfamily. Initial characterization of mutant cell lines containing disruptions in this gene, named racE, has revealed racE to be essential solely for cytokinesis, and all other aspects of Dictyostelium biology2 appear to be normal in these cells. A second gene has recently been identified which also functions in cytokinesis. We are still in the process of characterizing this gene but limited sequence analysis reveals strong homology to the mouse beige gene and the human gene responsible for the Chediak-Higashi syndrome. We are now in the process of trying to understand the cell biology and biochemistry of how these genes function in cytokinesis. Future work will include further characterization of these genes, as well as continuation of the screen to identify additional genes involved in cytokinesis.

Agarval, M.,N. Guerin, and D.A.Larochelle (2004). Chimeric analysis of the small GTPase RacE in cytokinesis sygnaling in Dictyostelium discoideum. Experimental Cell Research 295:226-235.

Abysalh, J.C.,LL.Kuchnicki and D.A.Larochelle (2002) The identification of Pats1, a novel gene locus required for cytokinesis in Dictyostelium discoideum. Molecular Biology of the cell 14:14-25

Guerin, N. and D.A.Larochelle (2003). A user's guide to restriction enzyme-mediated integration in Dictyostelium. (Accepted for publication in a special issue of the Journal of Muscle Research and Cell Motility dedicated to Dictyostelium research.)

Agarwal, M., D.J.Nelson, and D.A. Larochelle (2002). The three dimensional model of Dictyostelium discoideum RacE based on the human RhoA-GDP crystal structure. Submitted to the Journal of Molecular Graphics and Modeling 21:3-18.

Vithalani, K.K., C.A. Parent, E.M. Thorn, M. Penn, D.A. Larochelle, P.N. Devreotes, and A. De Lozanne (1998). Identification of Darlin, a Dictyostelium protein with Armadillo -like repeats that binds to small GTPases and is important for the proper aggregation of developing cells. Molecular Biology of the Cell 9:3095-3106.

Larochelle, D.A., K.K. Vithalani and A. De Lozanne (1997). The role of Dictyostelium racE in cytokinesis: Mutational analysis and localization studies by use of green fluorescent protein. Molecular Biology of the Cell 8:935-944.

Larochelle, D.A., K. Vithalani and A. De Lozanne (1996). A novel member of the rho family of small GTP-binding proteins is specifically required for cytokinesis. J. Cell Biology 133:1321- 1329.